NBME Surgery Shelf Incorrects Flashcards
A 36-year-old woman is admitted to the hospital because of bleeding in the upper gastrointestinal tract for 4 hours. Three months ago, she was hospitalized for 20 days for treatment of necrotizing pancreatitis secondary to choledocholithiasis. Four weeks ago, she was admitted for a similar episode of bleeding. Her temperature is 37.3°C (99.1°F), pulse is 110/min, and blood pressure is 110/70 mm Hg. The abdomen is soft with active bowel sounds. Endoscopy shows bleeding from gastric varices. The bleeding resolves with conservative treatment. Which of the following is the most likely cause of the bleeding?
A. Alcoholic hepatitis
B. Cirrhosis of the liver
C. Fatty infiltration of the liver
D. Hepatic vein thrombosis
E. Splenic vein thrombosis
Correct Answer: E Splenic vein thrombosis
Increased hydrostatic pressure and congestion in the portal venous system can lead to gastric and esophageal variceal formation, which have a high risk of life-threatening bleeding. Splenic vein thrombosis is a complication associated with pancreatitis and can lead to gastric variceal formation as some gastric veins drain into the splenic vein.
The patient’s presentation is most likely caused by splenic vein thrombosis resulting in variceal formation and subsequent upper gastrointestinal bleeding. The abdominal organs drain venous blood via both a systemic route (draining directly into the inferior vena cava) and the portal route (draining into the hepatic portal vein, then passing through the liver before entering the inferior vena cava). In the portal system, the inferior mesenteric veins and short gastric veins drain into the splenic vein, which then combines with the superior mesenteric vein to form the portal vein. Thrombosis in the portal system in this region is a potential complication of pancreatitis due to perivenous inflammation as the splenic vein lies in anatomic proximity to the pancreas. Clinical manifestations depend on the location of the thrombus. For this patient, a thrombus in the splenic vein led to venous congestion in the draining gastric veins and formation of gastric varices. In addition to gastrointestinal bleeding, other complications of splenic vein thrombosis can include hypersplenism, thrombocytopenia, intestinal ischemia, and increased risk of abdominal infection.
A 57-year-old woman with metastatic cancer of the sigmoid colon is admitted to the hospital because of a 2-day history of progressive swelling and pain of her right arm. Ten days ago, she underwent partial resection of the liver and placement of a right subclavian venous port. She currently takes no medications. Examination today shows a swollen, tender right forearm and hand. Venous duplex ultrasonography shows thrombosis of the right axillary and subclavian veins. The port and catheter are removed, and intravenous unfractionated heparin therapy (UHT) is begun.
On Admission:
Hg 9.2, HCT 28%, 8.9 WBC, PLT 260,000, PT 12, PTT 32 (INR 1)
2 Days of UHT:
Hg 9.6, HCT 27%, WBC 12.6, PLT 61,000, PT 13 (INR 1.1), PTT 87
What is the most likely diagnosis and next best step in management? Further treatment?
MLD: heparin induced thrombocytopenia (HIT)
NBS: stop heparin
further management: switch to DOAC
HIT typically occurs between 5 and 10 days after the initiation of heparin therapy. HIT results from the development of IgG antibodies against the complex of heparin and platelet factor 4. The antibody-heparin-platelet complex leads to the activation of platelets, which can cause thrombosis and consumption of platelets. This abnormal activation and consumption results in progressively decreasing platelet counts, which typically nadir at >50% of their initial level. Treatment requires cessation of all heparin- related products (e.g., unfractionated heparin and low-molecular-weight heparin). The patient should be transitioned to a direct thrombin inhibitor or direct factor Xa inhibitor to ensure adequate anticoagulation without worsening the thrombocytopenia.
Why can’t warfarin be used in early stages of HIT?
Warfarin therapy in the early stages of HIT can result in worsening of thrombosis because of transient hyper-coagulability from initial decreased concentrations of proteins C and S, and can increase the risk for gangrene of the extremities and skin necrosis.
An 18-year-old woman is brought to the emergency department 20 minutes after she sustained severe head injuries in a high-speed motor vehicle collision in which she was the unrestrained driver. Paramedics report finding a bottle of amphetamines inside the patient’s vehicle. On arrival, her Glasgow Coma Scale score is 6, and she is immediately intubated. Her pulse is 50/min, and blood pressure is 180/90 mm Hg. Examination shows numerous ecchymoses; lacerations over the face, trunk, and upper extremities; and right-sided hemotympanum. There are obvious facial fractures. Except for an abrasion over the right upper quadrant, abdominal examination shows no abnormalities. Which of the following is the most likely explanation for this patient’s increased blood pressure?
Increased intracranial pressure (Cushing’s reflex)
The Cushing reflex presents with systemic hypertension, bradycardia, and irregular respirations. It is observed during periods of increased intracranial pressure, often in the setting of impending herniation. As intracranial pressure rises, often because of intracranial bleeding (e.g., traumatic epidural or subdural hematoma) and/or cerebral edema, mean arterial pressure rises to maintain cerebral perfusion pressure. In response to rising mean arterial pressure, carotid baroreceptors trigger reflex bradycardia as an autoregulatory response. Irregular respirations occur because of compression of the pons and medulla, which control autonomic respiratory rate and pattern. The presence of the Cushing reflex suggests increased intracranial pressure in extremis and constitutes a neurosurgical emergency. Immediate treatment to decrease intracranial pressure is required, including administration of mannitol, hypertonic saline, hyperventilation, and elevation of the head of the bed with emergent decompressive surgery.
A 67-year-old woman with essential hypertension comes to the physician because of a 6-month history of moderate aching of her left arm when she carries grocery bags, does anything with the arm raised above her head, or lifts anything heavy. One week ago, while cleaning a large mirror, she felt dizzy and almost lost consciousness. She has not had chest pain, shortness of breath, or sweating. She is left-hand dominant. She takes no medications. She has smoked one pack of cigarettes daily for 40 years. Her pulse is 72/min and regular, and blood pressure in the left upper extremity is
115/85 mm Hg. Upper extremity pulses are normal. Muscle strength and sensation testing in the upper extremities shows no abnormalities.
What additional components of the physical examination is most likely to confirm the diagnosis? What is diagnosis? NBS?
Blood pressure measurement of the right upper extremity should be assessed to determine differential upper extremity blood pressures in the setting of possible subclavian steal syndrome. Subclavian steal syndrome occurs secondary to stenosis of the subclavian artery proximal to the origin of the vertebral artery. Movement and exertion of the affected upper extremity results in a reversal of flow from the ipsilateral vertebral artery into the subclavian artery to supply the upper extremity. This results in vertebrobasilar insufficiency, which can manifest as dizziness, vertigo, imbalance, light-headedness, and hearing disturbances. Most patients demonstrate differential blood pressures between the affected and unaffected upper extremities, with a greater than 15-mm Hg differential between the two. Physical examination may also demonstrate a subclavian bruit on auscultation and a reduction and/or delay in the ipsilateral radial pulse.
A previously healthy 6-year-old girl is admitted to the hospital because of a 2-day history of fever and progressive left hip pain. She has refused to bear weight on her left leg since awakening 4 hours ago. There is no history of trauma. She is now lying on the stretcher with her left leg abducted and externally rotated. Her temperature is 39.1°C (102.4°F), pulse is 130/min, respirations are 24/min, and blood pressure is 100/60 mm Hg. On examination, she resists any motion of the left lower extremity. There is warmth over the left hip but no erythema or swelling. Her erythrocyte sedimentation rate is
70 mm/h. Arthrocentesis of the left hip yields cloudy fluid; joint fluid analysis shows an erythrocyte count of 10,000/mm3 and
3
leukocyte count of 196,000/mm . Results of culture of the synovial fluid are pending. X-rays of the pelvis and left lower
extremity show no abnormalities. In addition to intravenous antibiotic therapy, what is the most appropriate next step in management? Most likely cause?
Septic arthritis.
NBS: surgical I&D
most likely bug: staph aureus
Septic arthritis is most commonly caused by Staphylococcus aureus and presents with pain, inability to bear weight, reduced range of motion, fever, chills, nausea, myalgias, arthralgias, and fatigue. Vital signs may disclose a fever, tachycardia, or hypotension if it is complicated by bacteremia or sepsis. Physical examination typically discloses tenderness to palpation of the affected joint, a limited range of motion, pain with range of motion, joint effusion, and overlying cutaneous erythema. Routes of infection include direct inoculation, spread from an adjacent infection such as osteomyelitis, or hematogenous seeding. Diagnosis is through physical examination plus arthrocentesis, which classically discloses a neutrophilic-predominant exudate with a leukocyte count greater than 50,000/mm . Organisms are often seen on Gram stain and are
detected by culture. Treatment includes intravenous antibiotics plus emergent surgical incision and drainage to prevent complications including articular erosion, fibrous ankylosis, loss of the ability to ambulate, and the potential for sepsis and even death if severe.
An 82-year-old man is admitted to the intensive care unit after undergoing an uncomplicated, elective sigmoid colectomy for chronic diverticulitis. He is extubated and rates his pain as a 2 on a 10-point scale. He has a history of coronary artery disease. His medications are atorvastatin, metoprolol, and aspirin. His temperature is 37.2°C (99°F), pulse is 110/min, respirations are 32/min, and blood pressure is 140/80 mm Hg. Pulse oximetry on 6 L/min of oxygen by nasal cannula shows an oxygen saturation of 92%. There is jugular venous distention. Expiratory wheezes are heard at both lung bases. What is the most likely diagnosis? Treatment?
-acute congestive heart failure.
-Treatment of an acute exacerbation of congestive heart failure consists of diuresis and respiratory support (eg, supplemental oxygen, positive pressure ventilation), and in more severe cases, intravenous positive inotropes and a ventricular assist device may be needed if cardiogenic shock is occurring.
Symptoms: tachycardia, tachypnea, hypoxemia, jugular venous distention, and end-expiratory pulmonary wheezes (sometimes referred to as a cardiac wheeze because of the association with pulmonary edema resulting from heart failure).
Other signs of CHF can include:
L-sided: SOB, dyspnea on exertion, orthopnea, and production of frothy sputum in left-sided failure
R-sided: increased JVP, hepatomegaly, ascites, and peripheral extremity edema.
Anesthesia and surgery place significant stress on the body, and myocardial demand can exceed cardiac output, especially in an older patient with underlying coronary artery disease. Additionally, surgeries complicated by blood loss and fluid shifting may result in the need for administration of several liters of crystalloid or blood product to maintain hemodynamic stability.
A 20-year-old man is brought to the emergency department 30 minutes after being involved in a motor vehicle collision. He was an unrestrained front-seat passenger during the head-on collision. The left lower extremity is flexed at the hip, shortened, adducted, and internally rotated. He is unable to dorsiflex the ankle.
-What is the most likely diagnosis?
-Treatment of choice?
-Risk for injury of what other structures?
Hip dislocation
posteriorly directed force during a motor vehicle collision (“dashboard injury”), where the femoral head is forcefully displaced posteriorly out of the acetabulum.
risk for injury to the sciatic nerve, and of avascular necrosis of the femoral head if there is compromise of the proximal femoral vasculature
Treatment requires closed reduction followed by abduction bracing of the hip. Reduction should not be delayed for imaging, as a shorter time to reduction is associated with fewer complications and improved outcomes.
A hospitalized 67-year-old man has chest pain 3 days after undergoing a left colectomy for adenocarcinoma of the sigmoid colon. He is diaphoretic. His temperature is 37.5°C (99.5°F), pulse is 110/min and regular, respirations are 16/min, and blood pressure is 95/75 mm Hg. The skin is cool. Crackles are heard halfway up the lung bases. Cardiac examination shows no murmurs or gallops. An ECG shows ST-segment elevation in leads II, III, and aVF.
On pulmonary artery catheterization, what do you expect the impacts will be on cardiac output, PCWP, SVR?
CO: decreased
PCWP: increased
SVR: increased
In cardiogenic shock, there is severe dysfunction of the cardiac myocytes, resulting in markedly decreased contractility. Pulmonary artery catheterization typically demonstrates decreased cardiac output and increased pulmonary capillary wedge pressure because of the underlying systolic cardiac dysfunction. Systemic vascular resistance is commonly increased as a physiologic attempt to maintain mean arterial pressure in the setting of reduced cardiac output and peripheral perfusion.
A 30-year-old male firefighter has been hospitalized for 3 weeks for treatment of third-degree burns involving the neck, upper anterior chest, and right upper extremity. A purulent exudate is noted at an intravenous catheter site located in the proximal cephalic vein just above the left wrist. When the catheter is removed, additional purulent exudate drains from the site. Temperature is 38.7°C (101.7°F), pulse is 115/min, respirations are 18/min, and blood pressure is 105/70 mm Hg. Physical examination shows an 8-cm segment of the cephalic vein that is firm, tender, indurated, erythematous, and fluctuant. In addition to intravenous broad-spectrum antibiotics, which of the following is the most appropriate next step in management?
Excision of the vein
Catheter-related bloodstream infections are a common cause of fever in hospitalized patients and can be complicated by catheter-associated septic thrombophlebitis. The infected thrombus serves as a nidus for microbial proliferation and presents with fever and signs and symptoms of bacteremia. The involved vein may display erythema and induration and there may be purulent drainage from the catheter site. The diagnosis may be aided by duplex ultrasonography or with contrasted CT scan. Treatment of catheter-associated septic thrombophlebitis includes infectious source control with removal of the catheter and surgical excision of the affected vein. Intravenous antibiotics should be continued and adjusted to microbial sensitivities, when possible.
Six days after abdominoperineal resection of the rectum for cancer, a 62-year-old woman becomes dyspneic as she walks to the bathroom. The postoperative course had been uncomplicated. Her temperature is 37.1°C (98.7°F), pulse is 135/min, respirations are 34/min, and blood pressure is 120/70 mm Hg. She is anxious and diaphoretic. The chest is clear to auscultation and there are no cardiac murmurs or gallops. There is no tenderness or edema of the lower extremities. What is the most likely cause?
A pulmonary embolism (PE) refers to an embolized blood clot to the pulmonary vasculature, most often from the deep veins of the lower extremities. Symptoms include dyspnea, pleuritic chest pain, hemoptysis, and, occasionally, lightheadedness or syncope. Clinical signs include tachycardia, tachypnea, hypoxia, and, if massive, hypotension. Risk factors for deep venous thrombosis (DVT) and subsequent PE include prolonged immobility, hypercoagulability, and tissue injury. Postsurgical DVT and consequent PE are common, as surgical patients, especially those with malignancy, have many of the risk factors that put them at increased risk for the development of venous stasis and clot formation. These often develop 5 to 7days after a procedure, and prophylaxis with subcutaneous heparin is frequently instituted to prevent their formation. Thus, in this cancer patient with dyspnea, tachycardia, and tachypnea 6 days following a surgical procedure, PE is the most likely diagnosis. Treatment includes therapeutic anticoagulation.
A previously healthy 32-year-old woman is brought to the emergency department 30 minutes after a motor vehicle collision. She was an unrestrained front seat passenger. On arrival, she has pain and tingling in her right leg and is unable to move it. Her pulse is 105/min, respirations are 18/min, and blood pressure is 155/90 mm Hg. The right lower extremity is pale. The dorsalis pedis and posterior tibial pulses are absent on the right. There is a posterior dislocation of the right knee. Motor and sensory function is absent below the right knee. Following reduction of the dislocation and splinting of the right lower extremity, the patient is able to move the leg. What is the most appropriate next step in diagnosis?
Arteriography
Posterior knee dislocation places traction on the popliteal artery and branches of the sciatic nerve. Such an injury can result in potential circulatory insufficiency and neurological deficits to the leg distal to the level of the injury, resulting in permanent loss of function if untreated. Prompt reduction of the knee dislocation serves to limit the extent of injury by relieving neurovascular traction, thereby minimizing damage and restoring nerve function and arterial flow. Arterial injuries sustained during a posterior knee dislocation can include dissection, rupture, thrombosis, and intramural hematoma; pseudoaneurysms can also occur. Prompt arteriography or CT/MR angiography is indicated to further investigate the presence of underlying arterial injuries and to facilitate operative repair planning.
